1. Field of the Invention
The present invention relates to an information display device, and more particularly, it belongs to a technical field of an information display device suitable for displaying an operation menu at the time of blind operation of on-vehicle apparatuses by a multifunction switch, the on-vehicle apparatuses being a navigation system, an audio apparatus, and so on mounted on a vehicle.
2. Description of the Related Art
Conventionally, a multifunction switch has been well known that is intended for use in operating a navigation system, an audio apparatus, an airconditioner, and so on by blind operation from a driver's seat or a front passenger's seat of a vehicle while the vehicle is being driven (for example, refer to Japanese Patent Laid-open No. 2000-276976).
This multifunction switch is so structured that operation switches are disposed at positions where respective fingers are situated when an operator holds the multifunction switch, thereby enhancing operability, and it is provided with a jog encoder switch with a push function, thereby realizing diversified switch operations. This multifunction switch enables an operator to operate the apparatuses by blind operation while seeing a hierarchical operation menu displayed on a display screen mounted on a vehicle.
In a conventional information display device using the above-described multifunction switch, the following two methods have been typically implemented as methods for displaying an operation menu on a display screen.
(1) Menu display is kept on stand-by at a normal time and the menu is displayed by switch operation. When no switch operation is executed for a predetermined period of time, the menu is erased from a display screen.
(2) A part of the screen is reserved as a menu display area for constantly keeping the menu displayed thereon.
However, the former method of the above prior arts requires, before the operation of the apparatus, switch operation for the display of an initial menu, which poses a problem of low operability.
In the latter method, the screen appears cluttered due to a large amount of information displayed on the screen. Moreover, an area for displaying other apparatus information becomes small. This is especially disadvantageous for a navigation function since a map display area is forced to be small.